1. Technical Field
The present disclosure relates generally to robotics and, more particularly, to a translational branch joint used in a parallel robot.
2. Description of Related Art
Parallel robots are widely used in modern industry because they provide advantageous precision and performance Referring to FIG. 4, a commonly used parallel robot 100 includes a support 11, a moving platform 12, and a pivot shaft 13 and three translational branch joints 15 connecting the support 11 with the moving platform 12. Each translational branch joint 15 includes a swing arm 151 and a four-bar linkage 152. The swing arm 151 is rotatably connected to the support 11. Four connecting bars of the four-bar linkage 152 are rotatably connected to each other via ball joints 153. Opposite ends of the four-bar linkage 152 are respectively fixed to the swing arm 151 and the moving platform 12. In use, the swing arm 151 is rotated by an electrical motor, such that the four-bar linkage 152 alters its parallelogram configuration in order to move the moving platform 12.
However, the ball joints 153 connecting the bars of the four-bar linkage 152 generally provide rotation angles of 25° or less. Thus the translational distance of the four-bar linkage 152 is limited, with the moving distance of the moving platform 12 restricted correspondingly. In addition, the ball joints 153 are difficult to machine and assemble, increasing the complexity and cost of manufacture.
Therefore, there is room for improvement within the art.